OK that's pretty much what I was talking about then. So my stupidly small transaction at the moment won't be accepted by most miners, which means it wont get recorded in the block chain which means it wont happen, right?
Yes, and right now it will sit in your wallet at 0 confirmations and get rebroadcast once in a blue moon (ok, not that long, but I'm too lazy right now to dig out the rules for when transactions are rebroadcast) until it DOES make it into a block.
And you'll have to hack your copy of bitcoin to be able to send a less-than-.01 transaction without a fee; the RPC send* methods automatically add the fee, and the GUI will tell you a fee is necessary (and won't let you send unless you agree to it).